UR CTU will consist of an Administrative Component and four Clinical Research Sites (CRSs). The UR CTU is proposing to affiliate with the HIV Vaccine Trials Network (HVTN) and the AIDS Clinical Trials Group (ACTG). Letters of commitment from Dr. Larry Corey, Principal Investigator of the HVTN, and Dr. Constance Benson, Principal Investigator of the ACTG, are included in the Section Consultants and Letters of Support. Of the four UR CTU CRSs, one will conduct studies for the HVTN and three will conduct studies for the ACTG. All four CRSs are currently main units or subunits of an existing HIV Vaccine Trials Unit (HVTU) or AIDS Clinical Trials Unit (ACTU). Two CRSs will be located at the UR Medical Center (URMC). One, the UR HVTN CRS, will conduct HVTN studies, and the other, the UR ACTG CRS will conduct ACTG studies. The third CRS will be located at AIDS Community Health Center (ACHC), in Rochester, New York and will perform ACTG studies. The fourth will be located at the State University of New York at Buffalo, the UB CRS, and will perform ACTG studies. The Administrative Core of the UR CTU will be located within the UR Infectious Diseases Division (IDD), which also contains the UR HVTN CRS and the UR ACTG CRS. The UR IDD has a long history of performing NIAID-supported clinical investigation and has been part of the HVTN and ACTG since both programs originated. As a consequence of this history, the IDD has developed approaches to sharing resources, which will be expanded in the proposed CTU. Centralized Clinical Research Functions will include a Processing Laboratory, a Flow Cytometry Laboratory, a Data and Quality Management Team, a Community Education and Outreach Program (CEOP), and an approach to Staff Training. These Functions will be shared by all four CRSs. The CTU will support the research agendas proposed in the HVTN and ACTG Leadership Applications by enrolling subjects in critical studies, focusing on areas in which UR CTU investigators have particular expertise and a demonstrated record of performance. UR CTU investigators will also make important scientific and administrative contributions to the HVTN and ACTG. The UR CTU will serve as a mentoring unit for a CTU based at the Federal University of Sao Paulo in Sao Paulo, Brazil. The research outlined in this proposal is designed to make contributions to the prevention and treatment of HIV infection and AIDS. The proposed UR CTU will affiliate with two large, multicentered programs, the HVTN and the ACTG. The goal of the HVTN is to develop a vaccine that will prevent HIV infection or delay the onset of symptomatic disease. The goal of the ACTG is to develop more effective treatments for established HIV infection in a variety of patient populations.